An aneurysm is an abnormal bulging or ballooning of an artery due to a weakness in the arterial wall. Intracranial or cerebral aneurysms, which occur in approximately 2% of the population, are frequently life-threatening when rupture occurs. Conventional treatment includes surgical clipping to bypass the aneurysm and endovascular coiling of the aneurysm. Endovascular coiling involves packing the aneurysm with small platinum coils to cause embolization of the aneurysm. Endovascular coiling has the advantage of being less invasive than surgical repair of intracranial aneurysms, because the coils are delivered by a catheter inserted into a femoral artery of the patient,
Although endovascular coiling has been effective in the treatment of narrow neck aneurysms, it is less effective in treating wide neck aneurysms. The irregular interface between the coil mass and the parent artery increases the risk of thrombosis leading to stroke, especially in wide neck aneurysms, Further, because filling the aneurysm sac with coils does not address the diseased parent artery segment, there remains a high risk of regional recurrence of an aneurysm. Stents have been used in stent-assisted coiling in the treatment of patients with wide-necked intracranial aneurysms to maintain the coils in place and to maintain the patency of the affected artery. However, stent-assisted coiling in the treatment of wide neck aneurysms is problematic due to challenges associated with the anatomical reconstruction of a large segmental parent artery defect and impaired durability of the affected vessel.
Ionita et al. described the use of a variable porosity stent with a low porosity patch that covers the aneurysm neck as a primary treatment of intracranial aneurysms (Ionita et al., 2009 Stroke 40:959-965). The variable porosity stents of Ionita, referred to as asymmetric vascular stents (AVS); were used to treat aneurysms in rabbits. Each of the nine rabbits treated with AVS showed complete occlusion of the aneurysm; however, three of the nine rabbits died subsequent to AVS treatment.
There is a need in the art for systems, stents, and methods of treating aneurysms that reduce inflow of blood from the aneurysm to the parent artery while minimizing risk of thrombogenic occlusion of the parent artery and/or heal the damaged vessel. The present invention satisfies that demand.